Group 4 (Ti and Zr) and 5 (Nb and Ta) atoms substituted into the ^*BEA zeolite framework (M-BEA) irreversibly activate hydrogen peroxide (H₂O₂) and form pools of metal-hydroperoxide (M-OOH) and peroxide (M-(η²-O₂)) intermediates active for the oxidation of 2,5-dimethylthiophene (C₆H₈S), a model reactant representative of organosulfur species in fossil reserves and chemical weapons. Sequential oxidation pathways convert C₆H₈S into 2,5-dimethylthiophene oxide (C₆H₈SO) and subsequently into 2,5-dimethylthiophene dioxide by oxidative dearomatization. Oxidation rates measured as functions of reactant concentrations together with in situ UV–vis spectra show that all M-BEA activate H₂O₂ to form pools of M-OOH and M-(η²-O₂), which then react with either C₆H₈S or H₂O₂ to form the sulfoxide or to decompose into H₂O and O₂, respectively. Turnover rates for C₆H₈S oxidation and H₂O₂ decomposition both increase exponentially with the electron affinity of the active site, which is quantitatively probed via the adsorption enthalpy for deuterated acetonitrile to active sites. C₆H₈S oxidation rates depend also on the nucleophilicity of the solvent used, and rates decrease in the order acetonitrile > p-dioxane ∼ acetone > ethanol ∼ methanol. In situ UV–vis spectra show that highly nucleophilic solvent molecules compete effectively for active sites, inhibit H₂O₂ activation and formation of reactive M-OOH and M-(η²-O₂) species, and give lower turnover rates. Consequently, this work shows that turnover rates for sulfoxidation are highest when highly electrophilic active sites (i.e., stronger Lewis acids) are paired with weakly nucleophilic solvents, which can guide the design of increasingly productive catalytic systems for sulfide oxidation.

取代入^* BEA沸石骨架（M-BEA）的第4组（Ti和Zr）和5（Nb和Ta）原子不可逆地激活过氧化氢（H ₂ O ₂）并形成金属过氧化氢（M-OOH）和过氧化物（M-（η ² -O ₂））的中间体活性2,5-二甲基噻（C氧化₆ ħ ₈ S），一个模型反应物代表在化石储量和化学武器的有机硫物质。顺序氧化途径将C ₆ H ₈ S转化为2,5-二甲基噻吩氧化物（C ₆ H ₈SO 2），然后通过氧化脱芳烃作用转化为2，5-二甲基噻吩二氧化物。作为反应物浓度的函数原位一起测量的UV-vis光谱显示所有的M-BEA激活ħ氧化速率₂ Ò ₂至M-OOH和M-的形式池（η ² -O ₂），然后与任一反应C ₆ H ₈ S或H ₂ O ₂分别形成亚砜或分解为H ₂ O和O ₂。C ₆ H ₈ S氧化和H ₂ O _2的周转率分解均随活性位点的电子亲和力呈指数增加，这通过氘化乙腈对活性位点的吸附焓进行定量探测。C ₆ H ₈ S的氧化速率还取决于所用溶剂的亲核性，并且速率降低的顺序依次为乙腈> 对二恶烷〜丙酮>乙醇〜甲醇。原位的UV-vis光谱显示高度亲核的溶剂分子为有效活性位点竞争，抑制ħ ₂ ö ₂激活和反应性M-OOH和M-的形成（η ² -O ₂）物种，并提供较低的周转率。因此，这项工作表明，当高度亲电的活性位点（即较强的路易斯酸）与弱亲核溶剂配对时，硫氧化的转化率最高，这可以指导硫化物氧化生产效率越来越高的催化体系的设计。